Siloxane compounds constitute an important class of industrial chemicals that are commonly found in organic copolymers of various forms including fluids, gels, elastomers, and resins. By modifying a siloxane with certain organofunctional groups and then linking these compounds to form an organic polymer, compositions can be formed having a wide variety of desirable physical and chemical properties such as improved impact resistance, flame resistance, heat stability, lubricity, and flow properties. Many of these compounds have use in such diverse applications as wetting agents, manufacturing processing aides, surfactants, foam control additives, pressure sensitive adhesives, thermoplastic elastomers, compatibilizing agents, water repellant materials, dry cleaning fluids, textile aids, personal and household care, preservatives, pesticides, and electronic circuits. In addition, many of these polymers and copolymers are non-toxic and environmentally compatible and can effectively be used in cosmetic and personal care products. Examples of modified siloxanes include aryl-functional silicone (see, e.g., U.S. Pat. No. 6,716,441); silicone acrylates (see, e.g., U.S. Pat. No. 6,630,133); amino-, epoxy-, and anhydride-functional silicones (see, e.g., US 2003/0162688); and silicone-fluoroalkyl polyether (see, e.g., JP 2006 045102).
Of particular interest to the present invention is siloxane polymers having aldehyde functionality. Aldehyde functional siloxanes are reactive with several synthetic and natural compounds. For example, aldehyde functional groups can react with sugars, starches, sucrose esters, and cellulose to form acetal derivatives, and with proteins, amino acids, and peptides to form imine derivatives.
Aldehyde functional siloxanes, particularly siloxane polymers having terminal aldehyde functionality, can also be utilized as part of a multifunctional polymer or copolymer by either blending two or more types of reactive polymers or by forming a copolymer comprising the aldehyde functional siloxane. These multifunctional polymers, which can have properties that are not achievable from their individual polymer ingredients alone, are particularly useful in formulating personal care products. For example, siloxane polymers and multifunctional copolymers can suspend biologically and/or cosmetically active ingredients via encapsulation, etc., and deliver these active ingredients to the desired site of activation such as the skin, nails, or hair. Using a siloxane polymer in this way can minimize the concentration of active ingredients of a personal care product (e.g., via time release dosing), thus reducing adverse side effects such as irritation. In addition, such polymers and copolymers provide for rheological control, hydrophobicity, emolliency, pigment dispersion, good film forming properties, lubrication, adhesion, foam control, surface modification, cationic/anionic surfactant, and can also provide a product with a desirable tactile impression such as soft-silky feel. Multifunctional polymers may also provide a more economic means of producing certain personal care products, e.g., by reducing the number of formulations required for a particular product line.
Aldehyde-functional siloxanes, as well as polymer and copolymers derived therefrom, have been described in WO 2006/014328 and WO 2006/014367, both of which are assigned to the same assignee as the present application and both of which are incorporated herein by reference.